The present invention relates to electronic musical instruments in general, and more particularly to improvements in register arrangements which are used in such instruments to influence tones which are generated by a tone generator and are selected and transmitted to the amplifier of a loudspeaker on actuation of keys or the like. Still more particularly, the invention relates to register arrangements wherein any one of a plurality of functional units can be activated by one of several electronic selector switches to thereby influence the tone signals. The selector switches are activatable by voltage signals which are transmitted to their control inputs by control conductors, and the register arrangement further comprises distributor circuits which include storages for programs and whose outputs can transmit signals on operation of actuating elements to apply the stored programs to the control conductors. At least some of the distributor circuits are interchangeable, i.e., they can be removed from the register assembly and replaced by different groups of distributor circuits.
A register arrangement of the above outlined character is disclosed in commonly owned U.S. Pat. No. 4,106,383 granted Aug. 15, 1978 to Wilfried Dittmar. The functional units of the patented register arrangement can be influenced in response to application of control voltages which are applied manually by actuating individual register switches to transmit signals to discrete control conductors or by resorting to the aforementioned distributor circuits which can apply voltage signals to combinations of control conductors. This contributes significantly to simplicity of operation of the instrument because, by the simple expedient of operating a given actuating element, one can select an entirely different program. Functional units serve, for example, for tone formation or for selection of a variety of different effects. It is known to employ filters which impart to a tone a certain color; envelope curve circuits to produce a tremolo, percussion or piano effect; voltage controls to produce a vibrato of Hawaii effect; and/or others.
It is also known to employ in such musical instruments a base plate which carries several cards each having a distributor circuit for a particular program which is stored by resorting to a diode matrix. It is further known to assemble a group of distributor circuits by resorting to a data storage which can be actuated in response to the application of addresses in binary code to transmit signals to control conductors by way of a signal processing circuit. A switchover device renders it possible to convert the outputs of the signal processing circuit into data inputs to thereby program the storage via individual register switches.
A drawback of such mode of programming is that it is time-consuming, especially in the course of the initial programming operation when the register assembly is to store a large number of programs. Moreover, the registering operation is not fully familiar to each and every player, especially when the construction of the register assembly is such that it allows for actuation of a substantial number of functional units. The players are often incapable of creating a register assembly which is worthy of reproduction into a corresponding registration, even if the instrument is designed to allow for such operation.